78 



ITOETH AMEEICAIT FAUNA. 



[no. 39. 



breadth, 26.7; mastoid breadth, 21.5; interorbital breadth, 7; alveolar 

 length of upper molar series, 8.5. 



Remarks. — TJiomomys operarius seems to be a very local form, 

 quite distinct from perpes, by which its range is closely surrounded, 

 but more nearly resembling alhatus in short rostrum and heavy 

 skull, and aureus in color. While clearly of the perpallidus group, 

 it seems not to have direct connection with any of the forms and 

 may well stand as described, a full species. It is confined to the 

 sandy alkaline soil along the east side of Owens Lake. 



Specimens examined. — Seventy-nine, from type locahty. 



THOMOMYS LATIROSTRIS Merriam. 

 Painted Desert Pocket Gopher. 



(PI. V, fig. 7.) 



Thomomys latirostris Merriam, Proc. Biol. Soc. Washington, XIV, 107, July 19, 1901. 



Type. — Collected at Little Colorado River, Painted Desert, Arizona 

 (at Tanners Crossing, northeast of San Francisco Mountain), by 

 C. Hart Merriam and Vernon Bailey, September 22, 1899. Type 

 specimen in U. S. Nat. Mus., Biological Survey collection. 

 Distribution. — Painted Desert, Ariz. (fig. 8). 



Characters. — Size medium, hind foot 33 mm.; skull flattened; 

 rostrum short and broad; ears very small; color orange-buff, much 

 as in aureus. 



Color. — Upperparts bright buffy yellow or pale orange-buff, without 

 trace of black-tipped hairs; ears dusky; nose grayish brown; under- 

 parts, feet, and tail white, with a tinge of sulphur yellow stain on 

 belly of type. Young, slightly less yellow, more buffy. 



Skull. — Narrow and flat, with wide, flat rostrum; nasals narrow in 

 the middle, spreading anteriorly; premaxillse unusually wide at 

 base of rostrum; incisors abruptly decurved at right angles to axis 

 of skull; interparietal broadly pentagonal; bullae small, about as 

 infulvus; basioccipital wide, flat, and keeled. 



Measurements. — Type ( ad.): Total length, 232; tail vertebrae, 

 79; hind foot, 33. Skull (of type): Basal length, 39; nasals, 14; 

 zygomatic breadth, 26; mastoid breadth, 21; alveolar length of upper 

 molar series, 8. 



Remarks. — While unique in characters, latirostris can best be placed 

 in the group with aureus (perpallidus) , with which it agrees in 

 abruptly decurved incisors and U-shaped pterygoids. It is evidently 

 an isolated form of restricted range. The type specimen was caught 

 in the sand dunes in the Painted Desert along the Little Colorado 

 River at Tanners Crossing, between Black Tank and Moencopie. 

 It is a very old male in thin summer pelage, a worn and faded por- 

 tion of which is disappearing over the posterior half of the body. 



